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WISER: Water Infrastructure for Schistosomiasis-Endemic Regions

EPSRC Global Challenges Research Fund project EP/P028519/1

Schistosomiasis, also known as bilharzia or 'snail fever', is a parasitic disease caused by infection with Schistosoma parasites. Infection occurs when parasite larvae (cercariae) in fresh water pass through the skin; those cercariae are released by snails previously infected with another larval stage (miracidia) from eggs in infected people's urine or faeces. Schistosomiasis affects an estimated 258 million people in 78 countries worldwide, with 90% of the infections occuring in Africa. It kills an estimated 280,000 people annually and ranks second only to malaria as the most common parasitic disease.

Treatment with the drug praziquantel is the primary form of treatment, with a single dose of the drug having been shown to reduce the burden of infection and severity of symptoms. However, re-infection will quickly occur when people are re-exposed to infested fresh water. Education campaigns about the risks of exposure to contaminated water and improved water supply and sanitation should in theory break the life cycle of the disease. Unfortunately however, there is very limited and incomplete information available regarding the effectiveness of water treatment processes at removing or inactivating cercariae of different Schistosoma. Also, there are no rapid means for detecting cercariae in water samples and determining their viability, which makes assessing the risk and degree of contamination of a water body and testing the effectiveness of water treatment processes as barriers against cercariae very difficult.